Drop libc.so.6 and libgiognutls.so from runtime deps (implicit or absent on musl)

MANIFEST.usm

@@ -30,10 +30,8 @@
       "lib:libglib-2.0.so.0",
       "lib:libgobject-2.0.so.0",
       "lib:libgio-2.0.so.0",
-      "gio:libgiognutls.so",
       "lib:libinvercargill-1.so",
       "lib:libinvercargill-json.so",
-      "lib:libc.so.6",
       "lib:libpcre2-8.so.0",
       "lib:libffi.so.8",
       "lib:libgmodule-2.0.so.0",